In Patent Literature 1, as shown in FIG. 8, proposed is a coating apparatus 101 that is provided with a pressurizing air line (constant pressure supply means) 120, a coating liquid tank 130, a supply pipe arrangement 140, a supply valve 150, a constant-volume pump (constant-volume supply means) 160, a discharging pipe arrangement 170, a discharging valve 180, a slit nozzle 190, a movable stage 200 and a control section. The pressurizing air line 120 is connected to the coating liquid tank 130, and supplies the air compressed with a compressor or the like to the interior of the coating liquid tank 130, thereby applying a constant pressure to a coating liquid in the coating liquid tank 130. The coating liquid tank 130 is connected to an inlet of the constant-volume pump 160 by the supply pipe arrangement 140. The supply valve 150 is disposed in the middle of the supply pipe arrangement 140, and a pneumatic transportation of the coating liquid is commenced following an opening action of the supply valve 150.
For the constant-volume pump 160, a piston pump in which a piston is disposed inside a cylinder in such a manner as to be capable of reciprocating motion or the like is employed, and displaces a constant volume of the coating liquid inside the cylinder as the piston is caused to perform a forward motion at a constant speed by an AC servo-motor or the like. An outlet of the constant-volume pump 160 is connected to the slit nozzle 190 by the discharging pipe arrangement 170. The discharging valve 180 is disposed in the middle of the discharging pipe arrangement 170, and following an opening action of the discharging valve 180, transportation of a constant volume of the coating liquid is commenced by the constant-volume pump 160.
Below the slit nozzle 190 is installed a movable stage 200 that moves at a constant speed. A leaflike work W such as glass substrate is sticked and held by suction on the movable stage 200. By discharging the coating liquid from the slit nozzle 190, the coating liquid is applied onto the work W that is moved together with the movable stage 200.
Operation of the coating apparatus 101 that is described in the Patent Literature 1 is explained. At a start of the coating, the control section 210, by causing the pressurizing air line 120 to be driven, the discharging valve 180 to shut and the supply valve 150 to open, raises the pressure inside the coating liquid tank 130. Then, the control section 210, by causing the discharging valve 180 to open and the supply valve 150 to shut, starts discharging the coating liquid from a front edge of the slit nozzle 190. At the same time, the control section 210, controlling the movable stage 200, causes either of the work W and the slit nozzle 190 to move relative to the other.
After that, the control section 210 causes the pressurizing air line 120 to stop, and sets the pressure inside the coating liquid tank 130 to return to the atmospheric pressure. Thereafter, transportation of the coating liquid is achieved by the constant-volume pump 160 alone with a flow rate maintained at a constant value, and thereby a coating process is performed with a uniform film thickness. At an end of the coating, the control section 210, by causing the discharging valve 180 to shut and the supply valve 150 to open, forcibly halts the supply of the coating liquid to the slit nozzle 190.